The armorer is separate from everything else that gives bonus armor. Hypothetically you could have the crown of protection and Armorer and stack armor on a creature. One from Armorer and unlimited from crown.

Sir Jason is correct. Royal Armorer interacts with only "armor +1" tokens. Everything else can exist simultaneously on a creature and it will not block the armorer's ability. If you use the Armorer first, you are still able to use the crown. If you use the crown first, you may not use the Armorer on the same creature.